1. Field of the Invention
This invention relates to the field of pacing and pacemakers for the human heart and, specifically, to emergency pacing required for disorders of cardiac conduction. The present invention relates to an electrode system that is inserted into a human heart for patients either with severe bradycardia or heart block to avoid loss of consciousness or even death, or to prevent such arrhythmias in those at risk.
2. Description of Related Art
Patients that have a medical condition such as severe bradycardia or heart block must have their hearts electrically paced in order to avoid loss of consciousness or even death. Heart block occurs when the electrical stimulation that originates in the SA node, located in the upper chamber of the heart known as the atrium, is unable to propagate to the lower node, named the AV node, to the main pumping chambers of the human heart named the ventricles. This condition is known as disorder of the cardiac conduction system. Heart block frequently develops suddenly without major warning. The net result is a dangerous slowing of the heart rate which leads to decreased, inadequate blood flow to the body, especially to the brain causing dizziness or loss of consciousness and may even cause death.
In the current state of the art, in an emergency, emergency transvenous pacing leads can be inserted into the right ventricle to stimulate the ventricle. This allows for pacing of the ventricles, but results in a loss of atrial ventricular synchrony. The atrium does not contract synchronously prior to the ventricle with “single chamber” ventricular pacing. This anomaly results in a marked reduction of pumping efficiency of the heart. With patients that are in a state of structural heart disease or myocardial infarction, atrial-ventricular synchrony becomes even more essential for adequate blood flow to the body. Thus, even in emergency situations, stimulating the ventricle only with transvenous pacing is less than an optimal solution to the problem.
Although a second lead (electrode) can be inserted into the right atrium to allow atrial-ventricular “dual chamber” pacing in its various forms known to cardiologists, this technique is time consuming and cumbersome to do in an emergency situation. Also, leads are frequently difficult to reliably anchor in the atrium. For these reasons, the practice of emergency atrial-ventricular sequential pacing is not as commonly accepted by the emergency medical communities as it could be, despite the general appreciation of its utility.
The present invention overcomes the problems in the prior art by providing an emergency pacemaker that will pace and sense both atrial and ventricular chambers and provide “dual chamber” control of the heart using a lead that can be safely and easily inserted into the heart in an emergency situation.
“Dual chamber” pacing refers to continuous monitoring of the spontaneous activity of the heart both in the atria and in the ventricles, interpreting the detected events according certain accepted algorithms and providing stimuli to the chambers as needed to maintain a physiologically appropriate rhythm.